The utility of silica hydride based stationary phases for dual-mode ultra high performance liquid chromatography separation of synthetic cathinone positional isomers.

Emerging drugs usually mimic the effects of traditional drugs, but are not always controlled due to the chemically altered structures. Positional isomers of emerging drugs are challenging to analyze because they challenge the separation and detection techniques commonly employed by forensic laboratories. The utility of silica hydride (SiH) stationary phases for the ultra high performance liquid chromatography (UHPLC) separation of synthetic cathinone positional isomers was studied in this manuscript. SiH phases are operable under both reversed phase (RPC) and aqueous normal phase (ANP) chromatographic conditions without the need to change solvent reservoirs. The separation of eight positional isomers of the synthetic cathinone, pentedrone, was investigated using five SiH phases, and compared to a classical dual column reversed phase (RP), hydrophilic interaction chromatography (HILIC) system, and to a bi-modal PFP column. Significant selectivity differences were observed using either a combination of a classical RP C18 and NP Silica columns or the various bi-modal columns. The SiH Silica-C column, which contains no derivatized ligands attached to the silica hydride backbone, not only gave the most orthogonal separation of the bi-modal columns, but provided a unique separation of all 8 positional isomers (resolution ≥ 1) using the combination of RPC and ANP. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.